1. Field of the Invention
This invention pertains generally to devices and methods for two dimensional and three dimensional imaging, and more particularly to devices and methods for quickly and accurately segmenting a target in a three dimensional image from the rest of the structure and to obtain the target's geometric information, such as volume and surface curvature.
2. Description of Related Art
The information acquired from the diagnostic imaging of the body of a patient is an essential part of the treatment plan of modern physicians. The identification of the location and the geometry of structural injuries or defects assist medical evaluations and surgical planning. For example, diagnostic imaging is vital to the clinical evaluation of the geometry of aneurysms, tumors, thromboses, inflammations, foreign objects, organs and other objects which can be identified in 3D images for treatment. Imaging is used to document the disease and to estimate the area which will be surgically removed or to estimate the area which needs surgical filling such as cosmetic surgical implants.
For example, computed tomography (CT) is a medical imaging procedure which is performed millions of times each year in the United States. CT scans allow physicians to look at images of the anatomy of the patient in individual “slices” or “sections”. A modern CT scanner can produce thousands of two dimensional images of a patient's body in areas that are difficult to diagnose like the head, thorax, abdomen, or pelvis.
Volumetric analysis from images is becoming increasingly important as imaging technology advances. Various imaging technologies such as magnetic resonance imaging (MRI), ultrasound, CT, and satellite images have been improved from 2D to 3D and 4D (3D+time).
Currently, methods that are capable of evaluating a 3D volume are very limited. A method to evaluate the volume from volumetric images in a timely fashion such as for use in medical clinical evaluation is not available. Existing technologies include (1) manually segmenting the target from either 2D image or 3D mesh followed by a mesh calculation to estimate the volume, and (2) deforming a sphere or ellipse shape to fill the target, and then using the volume of the sphere/ellipse to represent the volume of the target. Both of these methods are labor intensive and time consuming, and cannot produce accurate results for irregularly shaped objects.
There exists an immediate need to quantitatively document the geometry of objects and anatomical structures to assist with medical clinical evaluations. There is a need to quickly compute the geometry of aneurysms, tumors, thromboses, inflammations, foreign objects, organs and other structures which can be identified in images and reconstructed into 3D objects, with little human intervention.
Other medical applications in addition to clinical evaluation are also in need of tools for virtual surgery or surgical planning including an estimation of the volume of tissue that will be surgically removed or the volume needed for surgical implants or for research tools to quantitatively obtain the 3D geometry and volume of targets of interest such as individual cells or cell compartments.
The present invention satisfies these needs, as well as others, by providing an apparatus and method to quickly and accurately obtain geometrical information, such as curvature or volume of an object from multi-dimensional (3D or more) images. It can also be used as a semi-automatic segmentation method which separates an irregular shaped 3D target from the rest of the surrounding structure for imaging and analysis.